cc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations sys_mman/shm_open.c -o sys_mman/shm_open -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lintl -liconv
sys_mman/shm_open.c:6:41: error: ‘shm_open’ undeclared here (not in a function)
    6 | int (*foo)(const char *, int, mode_t) = shm_open;
      |                                         ^~~~~~~~